diff --git a/src/cli.py b/src/cli.py
new file mode 100644
index 0000000..e122dd6
--- /dev/null
+++ b/src/cli.py
@@ -0,0 +1,401 @@
+"""CLI interface for gitignore-generator."""
+import os
+import sys
+from pathlib import Path
+from typing import List, Optional
+
+import click
+
+from . import __version__
+from .config import Config
+from .detector import ProjectDetector
+from .generator import GitignoreGenerator
+
+
+@click.group()
+@click.version_option(version=__version__, prog_name="gitignore-generator")
+@click.option(
+    "--config",
+    "-c",
+    type=click.Path(exists=True, dir_okay=False, readable=True),
+    help="Path to configuration file",
+)
+@click.pass_context
+def main(ctx: click.Context, config: Optional[str]) -> None:
+    """A CLI tool that generates .gitignore files for any project type."""
+    ctx.ensure_object(dict)
+    config_obj = None
+    if config:
+        config_obj = Config.load(config)
+    ctx.obj["config"] = config_obj
+
+
+@main.command("generate")
+@click.argument(
+    "types",
+    nargs=-1,
+    type=click.Choice(
+        [
+            "python",
+            "javascript",
+            "typescript",
+            "java",
+            "go",
+            "rust",
+            "dotnet",
+            "php",
+            "ruby",
+            "django",
+            "flask",
+            "react",
+            "vue",
+            "angular",
+            "rails",
+            "laravel",
+            "spring",
+            "vscode",
+            "jetbrains",
+            "visualstudiocode",
+            "linux",
+            "macos",
+            "windows",
+            "docker",
+            "gradle",
+            "maven",
+            "jupyter",
+            "terraform",
+        ]
+    ),
+)
+@click.option(
+    "--output",
+    "-o",
+    type=click.Path(dir_okay=False, writable=True),
+    default=".gitignore",
+    help="Output file path (default: .gitignore)",
+)
+@click.option(
+    "--append/--overwrite",
+    default=True,
+    help="Append to existing file or overwrite (default: append)",
+)
+@click.option(
+    "--language",
+    "-l",
+    multiple=True,
+    type=click.Choice(
+        [
+            "python",
+            "javascript",
+            "typescript",
+            "java",
+            "go",
+            "rust",
+            "dotnet",
+            "php",
+            "ruby",
+        ]
+    ),
+    help="Programming language(s) to include",
+)
+@click.option(
+    "--framework",
+    "-f",
+    multiple=True,
+    type=click.Choice(
+        [
+            "django",
+            "flask",
+            "react",
+            "vue",
+            "angular",
+            "rails",
+            "laravel",
+            "spring",
+        ]
+    ),
+    help="Framework(s) to include",
+)
+@click.option(
+    "--ide",
+    "-i",
+    multiple=True,
+    type=click.Choice(["vscode", "jetbrains", "visualstudiocode"]),
+    help="IDE(s) to include",
+)
+@click.option(
+    "--os",
+    multiple=True,
+    type=click.Choice(["linux", "macos", "windows"]),
+    help="Operating system(s) to include",
+)
+@click.option(
+    "--tools",
+    "-t",
+    multiple=True,
+    type=click.Choice(
+        ["docker", "gradle", "maven", "jupyter", "terraform"]
+    ),
+    help="Tool(s) to include",
+)
+@click.option(
+    "--stdout",
+    is_flag=True,
+    default=False,
+    help="Output to stdout instead of writing to file",
+)
+@click.pass_context
+def generate(
+    ctx: click.Context,
+    types: tuple,
+    output: str,
+    append: bool,
+    language: tuple,
+    framework: tuple,
+    ide: tuple,
+    os_opts: tuple,
+    tools: tuple,
+    stdout: bool,
+) -> None:
+    """Generate a .gitignore file for the specified types."""
+    config = ctx.obj.get("config")
+
+    generator = GitignoreGenerator(config)
+
+    if types:
+        for t in types:
+            generator.add_template(t)
+    else:
+        selected_types = list(language) + list(framework) + list(ide)
+        selected_types.extend(list(os_opts))
+        selected_types.extend(list(tools))
+
+        if not selected_types:
+            detector = ProjectDetector(Path.cwd())
+            detected = detector.detect()
+            for t in detected:
+                generator.add_template(t)
+            if not detected:
+                click.echo(
+                    "No project type detected. Please specify types manually.",
+                    err=True,
+                )
+                click.echo(
+                    "Use --language, --framework, --ide, --os, or --tools option.",
+                    err=True,
+                )
+                sys.exit(1)
+        else:
+            for t in selected_types:
+                generator.add_template(t)
+
+    content = generator.generate()
+
+    if stdout:
+        click.echo(content)
+    else:
+        output_path = Path(output)
+        if output_path.exists() and append:
+            mode = "a"
+        else:
+            mode = "w"
+        try:
+            with open(output_path, mode) as f:
+                f.write(content)
+            click.echo(f"Successfully wrote to {output_path}")
+        except PermissionError:
+            click.echo(f"Permission denied: {output_path}", err=True)
+            sys.exit(1)
+        except OSError as e:
+            click.echo(f"Error writing to {output_path}: {e}", err=True)
+            sys.exit(1)
+
+
+@main.command("detect")
+@click.argument(
+    "path",
+    type=click.Path(exists=True, file_okay=False, readable=True),
+    default=".",
+)
+@click.pass_context
+def detect(ctx: click.Context, path: str) -> None:
+    """Detect project type(s) from directory structure."""
+    detector = ProjectDetector(Path(path))
+    detected = detector.detect()
+
+    if detected:
+        click.echo("Detected project types:")
+        for t in detected:
+            click.echo(f"  - {t}")
+    else:
+        click.echo("No known project type detected.")
+
+
+@main.command("list")
+@click.option(
+    "--category",
+    "-c",
+    type=click.Choice(
+        ["language", "framework", "ide", "os", "tools", "all"]
+    ),
+    default="all",
+    help="Category to list (default: all)",
+)
+def list_templates(category: str) -> None:
+    """List available template types."""
+    templates = {
+        "language": [
+            "python",
+            "javascript",
+            "typescript",
+            "java",
+            "go",
+            "rust",
+            "dotnet",
+            "php",
+            "ruby",
+        ],
+        "framework": [
+            "django",
+            "flask",
+            "react",
+            "vue",
+            "angular",
+            "rails",
+            "laravel",
+            "spring",
+        ],
+        "ide": ["vscode", "jetbrains", "visualstudiocode"],
+        "os": ["linux", "macos", "windows"],
+        "tools": ["docker", "gradle", "maven", "jupyter", "terraform"],
+    }
+
+    if category == "all":
+        for cat, items in templates.items():
+            click.echo(f"{cat.capitalize()}:")
+            for item in items:
+                click.echo(f"  - {item}")
+    elif category in templates:
+        click.echo(f"{category.capitalize()}:")
+        for item in templates[category]:
+            click.echo(f"  - {item}")
+
+
+@main.command("wizard")
+@click.pass_context
+def wizard(ctx: click.Context) -> None:
+    """Interactive wizard to generate .gitignore."""
+    click.echo("=== gitignore-generator Wizard ===")
+    click.echo("")
+
+    languages = [
+        "python",
+        "javascript",
+        "typescript",
+        "java",
+        "go",
+        "rust",
+        "dotnet",
+        "php",
+        "ruby",
+    ]
+    frameworks = [
+        "django",
+        "flask",
+        "react",
+        "vue",
+        "angular",
+        "rails",
+        "laravel",
+        "spring",
+    ]
+    ides = ["vscode", "jetbrains", "visualstudiocode"]
+    oss = ["linux", "macos", "windows"]
+    tools = ["docker", "gradle", "maven", "jupyter", "terraform"]
+
+    selected = []
+
+    click.echo("Select programming languages (space-separated, Enter to skip):")
+    for idx, lang in enumerate(languages, 1):
+        click.echo(f"  {idx}. {lang}")
+    selected_langs = click.prompt(
+        "Languages", default="", type=str
+    ).split()
+    for lang in selected_langs:
+        if lang in languages:
+            selected.append(lang)
+
+    click.echo("")
+    click.echo("Select frameworks (space-separated, Enter to skip):")
+    for idx, fw in enumerate(frameworks, 1):
+        click.echo(f"  {idx}. {fw}")
+    selected_fws = click.prompt(
+        "Frameworks", default="", type=str
+    ).split()
+    for fw in selected_fws:
+        if fw in frameworks:
+            selected.append(fw)
+
+    click.echo("")
+    click.echo("Select IDEs (space-separated, Enter to skip):")
+    for idx, ide in enumerate(ides, 1):
+        click.echo(f"  {idx}. {ide}")
+    selected_ides = click.prompt("IDEs", default="", type=str).split()
+    for ide in selected_ides:
+        if ide in ides:
+            selected.append(ide)
+
+    click.echo("")
+    click.echo("Select operating systems (space-separated, Enter to skip):")
+    for idx, os_name in enumerate(oss, 1):
+        click.echo(f"  {idx}. {os_name}")
+    selected_oss = click.prompt("OS", default="", type=str).split()
+    for os_name in selected_oss:
+        if os_name in oss:
+            selected.append(os_name)
+
+    click.echo("")
+    click.echo("Select tools (space-separated, Enter to skip):")
+    for idx, tool in enumerate(tools, 1):
+        click.echo(f"  {idx}. {tool}")
+    selected_tools = click.prompt("Tools", default="", type=str).split()
+    for tool in selected_tools:
+        if tool in tools:
+            selected.append(tool)
+
+    if not selected:
+        click.echo("No templates selected.")
+        sys.exit(0)
+
+    config = ctx.obj.get("config")
+    generator = GitignoreGenerator(config)
+
+    for t in selected:
+        generator.add_template(t)
+
+    content = generator.generate()
+
+    click.echo("")
+    click.echo("Preview of generated .gitignore (first 50 lines):")
+    click.echo("-" * 50)
+    for idx, line in enumerate(content.split("\n")[:50]):
+        click.echo(line)
+    if len(content.split("\n")) > 50:
+        click.echo(f"... and {len(content.split('\\n')) - 50} more lines")
+    click.echo("-" * 50)
+
+    if click.confirm("Write to .gitignore?"):
+        output_path = Path(".gitignore")
+        mode = "a" if output_path.exists() else "w"
+        try:
+            with open(output_path, mode) as f:
+                f.write(content)
+            click.echo(f"Successfully wrote to {output_path}")
+        except PermissionError:
+            click.echo(f"Permission denied: {output_path}", err=True)
+            sys.exit(1)
+        except OSError as e:
+            click.echo(f"Error writing to {output_path}: {e}", err=True)
+            sys.exit(1)
+    elif click.confirm("Output to stdout instead?"):
+        click.echo(content)